Pond Liner Underlay 60gsm | Lightweight Geotextile Fleece | Budget Grade

Pond Liner Underlay 60gsm – Lightweight Protection for Smooth, Well-Prepared Ground

If you are lining a pond on ground that is already fine, sandy or stone-free, you still want a buffer between the soil and the liner, but you may not need a heavy-duty fleece. This 60gsm pond liner underlay is the lightweight grade: a thin, flexible geotextile fleece that lies under your liner and takes the rub from grit, small stones and fine roots. It is sold in 93 sizes from 2m x 2m up to 45m x 40m, so you can order the same footprint as your liner and cover the whole excavation in one go. It suits budget builds, small wildlife ponds, temporary or short-life water features, and contractors who want an economical layer on carefully prepared beds.

Why it works

A separating layer, not a cushion

At 60 grams per square metre, this underlay is thin and light. Its job is to stop the liner sitting directly on soil, where grit and small stones can scuff and abrade the membrane as the pond fills, settles and moves through the seasons. Because it is lightweight it drapes closely into shelves, slopes and corners without bulky folds, which makes it quick to lay and easy to tuck under edging.

Sized to your liner

Order the same size as your liner and you have enough underlay to cover the full footprint, including the overlap around the edge. The ordered area is supplied as sheets of 8m x 2m or 5m x 2m, which you lay side by side and overlap at the joins. Sheets are easier to handle on site than one large piece, and they let you work around plant shelves a strip at a time.

Know its limits

A 60gsm fleece is not designed to stop sharp flints, tree roots or rubble. On stony, flinty or root-filled ground, or under a koi pond with heavy rockwork, choose our 200gsm heavy-duty underlay instead.

• 60gsm lightweight geotextile underlay
• 93 sizes from 2m x 2m to 45m x 40m
• Supplied as 8m x 2m or 5m x 2m sheets covering the ordered area
• Goes under any flexible pond liner

Where it's used

Garden and wildlife ponds dug in sandy or loamy soil, raised and timber-framed ponds where the base is boarded or smooth, bog gardens and shallow marginal areas, temporary water features at shows and events, and contract landscaping jobs where the bed has been raked, screened and sanded before lining. It is also handy as an extra separating layer over a sand bed.

Specifications

Choosing the right option

Start with your liner size. Work it out as pond length plus twice the maximum depth plus the edge overlap, and the same for the width; our pond planner does the sum for you. Then choose the underlay size that matches or exceeds the liner in both directions. If your exact size is not listed, go up to the next size that covers both dimensions, because any surplus can be folded under at the edge or used as a second layer on the floor of the pond.

Next, decide on the weight. Choose this 60gsm grade when the ground is smooth and you have removed stones, roots and debris, or where the pond is small and shallow. Choose our 200gsm heavy-duty underlay for stony or flinty soil, ponds with heavy rocks or plant baskets on the base, koi ponds, and anywhere you want the most protection. Many builders use 200gsm on the floor and 60gsm on gentle, stone-free sides.

Installation, use & care

Clear the excavation of stones, roots and anything sharp, then firm and smooth the surface. Lay the sheets from the deepest point outwards, overlapping each join by at least 300mm, and press the fleece into the shelves and corners. Hold the edges with smooth stones while you position the liner on top, then trim any excess once the pond is full and the edging is in place. Store unused sheets dry and rolled.

Frequently asked questions

Is 60gsm thick enough for my pond?

It is suitable on ground that is already smooth and free of stones and roots. It is a separating layer rather than a puncture barrier, so on stony or flinty ground use 200gsm.

Will the underlay arrive as one piece?

No. The ordered size is supplied as sheets of 8m x 2m or 5m x 2m that together cover the area. Overlap the sheets by at least 300mm.

Can I use it on top of the liner?

Yes. A layer laid over the liner under rocks or pebbles helps protect the liner from above. For heavy rockwork the 200gsm grade is the better choice.

What size should I order?

Order the same size as your liner, or the next size up that covers both length and width.

Ordering & delivery

Choose your size from the list and add it to your basket alongside your liner. Delivery options and costs are shown at checkout before you pay. If you are unsure which size or weight you need, contact us with your pond dimensions and we will help you work it out.